4-(2-Fluorophenyl)-6-methyl-2-(1-piperazinyl)thieno[2,3-D]pyrimidine monohydrate hydrochloride is known (see U.S. Pat. No. 4,695,568) and has shown activity as an antidepressant. It has serotonin and noradrenergic reuptake blocking properties and this is thought to be the mechanism for its action as an antidepressant. The compound also has 5HT-3 blocking activity.
Functional bowel disorders are very common and include irritable bowel syndrome (IBS) and functional dyspepsia. IBS is the most common disorder diagnosed by gastroenterologists and one of the more common encountered in general practice. The overall prevalence rate is similar (approx 10%) in most industrialised countries. Some estimates of prevalence have reached 20%. The illness has a large economic impact on health care use and indirect costs, chiefly through absenteeism.
IBS falls into two categories of equal prevalence, constipation-predominant and diarrhoea-predominant. The available treatments are generally poor.
A recent approach to treating diarrhoea-predominant IBS has involved the use of alosetron. This drug works by blocking the 5HT-3 receptor. Other drugs with this mechanism of action have shown some limited activity in this disease, including granisetron. Alosetron, although effective, was withdrawn due to side-effects on the colon.
A recent approach to treating constipation-predominant IBS involved agonising the 5HT4 receptor. Two such agonists are in clinical trials, i.e. tegaserod and prucalopride. Other approaches being explored include using 5HT1 agonists such as buspirone.
Functional dyspepsia is characterised by impaired accommodation of the stomach to a meal and epigastric pain discomfort or pain. There is often early satiety and weight loss. The disorder is not well understood. Treatments include antispasmodics and drugs affecting gut motility. Early studies suggest that buspirone and serotonin reuptake inhibitors may be useful.